1. Field of the Invention
The present invention relates to an apparatus for providing insulation against radiant, conductive, and convective heat transmission in areas in which only relatively thin insulators may be installed. This apparatus may take the form of a shade and may be used to insulate areas such as windows and doors in residential, commercial, and industrial buildings that ordinarily are relatively good heat transmitters.
It has become increasingly apparent in recent years that presently known sources of energy derived from the earth are finite and are, in fact, being rapidly depleted. Therefore, energy conservation has become a subject of great national concern.
The heating and cooling systems of residential, industrial, and commercial buildings use approximately 25% of all energy consumed in the United States. It is important to note, therefore, that transparent single pane or double insulated pane windows in these buildings are very poor heat insulators and consequently represent a significant cause of inefficient energy consumption. For example, in winter the heat loss per unit area through windows is typically three to ten times as great as that through adjacent walls depending on the type of wall insulation. Similarly, in summer the total heat entering through a sunlit window may be more than ten times that through the adjacent wall. (See, ASHRAE, Handbook of Fundamentals (1972); R. C. Dix and Z. Lavan; "Window Shades and Energy Conservation"; Mechanics, Mechanical and Aerospace Engineering Department, Illinois Institute of Technology, 1974). Therefore, substantial amounts of energy can be saved if window areas are effectively insulated. However, it is desirable to do so without permanently blocking windows and thus preventing their use for ventilation as well as for visual access to the outside world.
It may also be advantageous to insulate other areas where the permissible thickness of insulation is limited.